icpx fails test memory_scalar with -O3

[bernhardmgruber]

With changes in PR: #292

Testcase

int main() {
    using V = Vc::native_simd<short>;
    Vc::Memory<V, 53> m1, m2;
    m1.setZero();
    m2.setZero();
    m1 += 1;
    return m1 != m2;
}

Actual Results

0

Expected Results

1

Godbolt: https://godbolt.org/z/8heTYahbf

The problem goes away if we use -O2 instead of -O3.